This invention relates generally to electronic flames or radio frequency (R.F.) energy beams in combination with laser beams to provide an energy system for communications, for heating and for otherwise operating on workpieces. Much of the background of the R.F. energy beam portion of this invention may be found in the U.S. Pat. No. 3,648,015, issued to Thomas E. Fairbairn on Mar. 7, 1972.
The R.F. energy portion of the beam, which is generally known, is generated by a conventional radio frequency generator having a tank coil in its output circuit. The tank coil is a hollow metal tube into which inert gas is introduced under pressure. The output of the tank coil is coupled through a nozzle having an electrode mounted therein, and upon application of power to the radio frequency generator, an R.F. electron energy beam is emitted from the tip of the electrode and this beam is sheathed and focused by the inert gas.
Unsuccessful attempts have been made to treat certain metals with lasers prior to my invention. For example, it is not yet possible to perform deep penetration welding of aluminum with only a laser, because aluminum has a mirror like finish, and lasers have a high index for reflection off of aluminum. Furthermore, the present laser welding units, to weld other metals, require lasers generating in excess of 10 kilowatts of power at a cost of about $50 per watt, or a total cost in excess of $500,000.
The present invention contemplates a method and apparatus for providing a composite laser-radio frequency energy beam system. Prior to my conception of this invention, it was not known that the laser beam could be utilized in conjunction with an R.F. plasma type energy beam.
The present invention includes a radio frequency energy beam generator such as a torch, modified over the torch described in my U.S. Pat. No. 3,648,015, and combined with a laser generator. The torch of the present system includes a nozzle having a hollow electrode mounted therein. The laser beam is focused through the hollow portion of the electrode, without hitting the inner surface of the electrode, along with a low pressure gas. The laser is focused on a workpiece such as by an adjustable Cassegranian reflector. The energy beam generator is generally set forth in my prior patent, and upon energization of the radio frequency generator and introduction of an inert gas, the hollow electrode emits the coherent R.F. plasma energy beam. The R.F. plasma energy beam is sheathed or surrounded by an annular ring of inert gas which limits the scattering of the beam.
It is an object of the present invention to provide an improved oxidation resistant energy system which has a high energy level and heats work much faster and more controllably in a unit area of a target than prior art systems. Because of these features, the workpiece may be moved more rapidly through the beam for deep penetration fusion welds.
It is another object of the present invention to provide an energy system which permits point focusing of an intense portion of the summation of both energy beams for rapid traversing of the work, regardless of surface reflectivity of the target.
The present invention provides for a continuous beam which requires less peak power for deep penetration welding of metals including aluminum, and ceramics at a cost reduction of 10 times that of present lasers.